The Sentinelese, generally considered the last pre-Neolithic tribe in the world, have violently resisted any contact with outsiders

Portman found "ten men on the beach who were naked with long hair", he wrote in his 1899 book, A History Of Our Relations With The Andamanese, claiming they were fearful of him and reacted aggressively.

But it has emerged that Mr Portman actually kidnapped the tribesmen, and made them pose in a number of "homoerotic compositions" to "indulge his passion for photography".

A lawyer using the account Respectable Law, tweeted: "There's been a lot of talk about the missionary killed by the natives of North Sentinel Island.

"They're probably so aggressive because of this weirdo, Maurice Vidal Portman.

"So here's a big thread about this creep and some facts from my decade-long obsession with the island.

"He indulged his passion for photography by kidnapping members of various tribes and posing them in mock-Greek homoerotic compositions.

The tribe reportedly shot the US Citizen with arrows when he arrived on the shore

"During his 20 years in a sexualised heart of darkness, Portman measured and catalogued every inch of his prisoner’s bodies, with an obsessive focus on genitalia.”

The lawyer also claimed that each time Mr Portman returned to the island, the Sentinelese hid from him.

Survival International, a human rights organisation that campaigns for the rights of indigenous tribal people, has suggested that Mr Portman’s antics might spurred the hostility that the Sentinelese now show to outsiders.

Their website explains: "It is not known how many Sentinelese became ill as a result of this ‘science’ but it’s likely that the children would have passed on their diseases and the results would have been devastating.

“It is mere conjecture, but might this experience may account for the Sentinelese’s continued hostility and rejection of outsiders?”

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Since Mr Portman touched down on the island, brief visits have been paid but the Sentinelese remain untouched by modern civilisation.

Chau's death has sparked outrage in India, with government officials insisting that visitors stay away from the island.

A group of anthropologists, journalists and activists said in a joint statement that continuing with the efforts to recover Chau's body could lead to further violence and "completely unwarranted loss of life".

US missionary John Chau who was shot dead with arrows by tribe on remote island may still be ALIVE, friends and family believe

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